An ignition apparatus having twin spark high-voltage outputs incorporates features of a pencil coil wherein at least a portion of a transformer assembly is disposed within a spark plug well when installed in an internal combustion engine, thereby reducing the space required on the top of the engine. A secondary winding spool is configured to retain a secondary winding in first and second portions, wound either the same way for use in waste spark ignition systems or in opposite orientations for two-plug-per-cylinder systems. An alternate configuration includes an isolated shield that is internal to the case.